The present invention relates generally to electric fence monitors. More particularly, this invention pertains to providing continual audible and visual indicators of an operating condition (i.e., presence or absence of a fault condition) of a segment or length of electric fence.
Electric fences are used by ranchers and farmers to keep animals in a designated area or out of a designated area. Electric fences include a length of conductive material (i.e., the fencing) isolated from earth ground by insulators. The length of conductive material is connected to a fence charger (i.e., electric fence box). Checking and repairing fences is a major part of a farmer or rancher's job often requiring significant time and/or manpower. Faults in the electric fence are caused by animals running through the fence, plants growing up to the electric fence, or plants (e.g., trees) falling on the electric fence. Determining a fault in an electric fence and finding the source of the fault is often time-consuming because the fence must be manually tested to track the source of the fault. In operation, the electric fence charger periodically sends a pulse of static electricity along the electric fence. Parasitic resistances and capacitances bleed much of the energy from the fence between pulses.
When working properly, the electric fence should periodically exhibit over 5000 volts on a tester when energized by the electric fence charger. A user momentarily connects the tester to the electric fence to determine a voltage on the fence. This process is repeated around the fence until the user determines a segment of the fence having the fault condition. Active, self-powered testers are limited by their battery life or to a location with powerline power available. Passive testers are capacitive or resistive based and draw down the voltage on the fence. Therefore, they cannot remain connected to the fence during normal operation (i.e., at all times). There are no passive testers that permanently connect to an electric fence to continually indicate the status (fault or no fault) of a length of electric fence between the tester and the electric fence charger (i.e., electric fence box).
Providing a stable earth ground connection to an electric fence tester or monitor is accomplished by driving a grounding spike into the ground and electrically connecting the electric fence monitor or tester to the grounding spike. However, this requires the additional part of a grounding spike, and a single grounding spike may not provide a sufficient connection to earth ground or may become insufficient over time (e.g., via corrosion).
Alternatively, in a multi-strand fence, a designated one of the fence strands can be electrically connected to standard steel T-posts (safety posts) supporting the fence strands. The T-posts are driven into the ground, connecting the designed fence strand to earth ground. The electric fence monitor or tester is connected to the designated fence strand, providing the earth ground for the electric fence monitor or tester. However, this method of providing earth ground results in the designated strand being grounded to earth ground and providing little containment in addition to that provided by the other fence strands.